Everything below concerns gamma-glutamyl cycle. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
Biosynthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine, forming gamma-glutamylcysteine; glutathione synthetase then adds glycine to produce the complete tripeptide. Because the peptide bond from glutamate uses the gamma-carboxyl group, glutathione resists digestion by many ordinary peptidases. Tissues vary in synthesis capacity, and the liver generally contains high concentrations relative to many other organs. This uneven distribution contributes to organ-specific differences in redox buffering and affects how experimental results are interpreted across tissue types.
Glutathione participates in detoxification reactions, amino acid transport, and the maintenance of protein thiols. It serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. In research literature, altered glutathione status appears in studies of aging, infection, metabolic stress, and environmental exposure. Whether low glutathione is a cause, consequence, or marker of such conditions often remains unresolved. Direct measurement in blood or tissue provides a snapshot, but results depend on sample handling, timing, and the method used.
Synthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine. The first step is rate-limiting and is influenced by cysteine availability and feedback inhibition by GSH. Breakdown involves gamma-glutamyl transferase and subsequent peptidases, which release constituent amino acids for reuse. Because turnover differs among tissues, measurements from blood, plasma, and tissues are not directly interchangeable. Research continues to clarify how compartment-specific pools are regulated in health and disease.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It contains an unusual gamma-glutamyl bond between glutamate and cysteine, which resists cleavage by many peptidases. The reduced form, GSH, carries a thiol group on cysteine and is the dominant intracellular form in most cells. Its structure allows it to participate in redox reactions and to serve as a sulfur donor. The oxidized form, GSSG, consists of two GSH molecules joined by a disulfide bond.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced glutathione (GSH); oxidized form differs by disulfide linkage. |
| Molar mass | 307.32 g/mol | Calculated for the reduced tripeptide. |
| Appearance | White to off-white crystalline powder | Typical laboratory reagent description. |
| Solubility | Soluble in water | Aqueous solutions are acidic; solubility depends on pH and salt form. |
| CAS Registry Number | 70-18-8 | Refers to reduced L-glutathione; oxidized form has a different number. |
In its reduced form, glutathione carries a sulfhydryl group that can donate electrons. This property lets it act as a major cellular antioxidant and redox buffer. Glutathione peroxidase uses it to reduce hydrogen peroxide and lipid peroxides, while glutathione reductase regenerates the reduced form using NADPH. The ratio of reduced glutathione to glutathione disulfide is widely used as an indicator of oxidative stress, though the ratio changes with compartment, cell type, and sample handling. Oxidized glutathione can also form mixed disulfides with proteins, affecting their activity.
Glutathione supports detoxification by conjugating reactive electrophiles through glutathione S-transferases. The resulting conjugates are processed and exported, often after further metabolism. It also stores cysteine, transports amino acids across membranes through the gamma-glutamyl cycle, and assists in the maturation of iron-sulfur clusters and some prostaglandins. In plants, animals, and many microbes, the molecule appears in similar roles, but concentrations vary enormously between tissues. Liver, kidney, and red blood cells tend to contain high amounts, while blood plasma contains much less.
Glutathione is a small tripeptide composed of glutamate, cysteine, and glycine, with the unusual gamma-glutamyl linkage between glutamate and cysteine. Its cysteine thiol group makes it a major non-enzymatic antioxidant in cells. The reduced form, GSH, predominates in most intracellular compartments, while the oxidized disulfide form, GSSG, is produced when GSH reduces reactive oxygen species. Intracellular concentrations often reach millimolar levels, whereas plasma concentrations are much lower, typically in the low micromolar range. This gradient reflects active synthesis, transport, and consumption rather than passive distribution.
Synthesis occurs in two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine to complete the tripeptide. The pathway is feedback-inhibited by GSH and limited by cysteine availability, so cysteine supply often constrains production. Once formed, GSH participates in redox buffering, xenobiotic conjugation, and protein glutathionylation. Glutathione peroxidase uses GSH to reduce hydrogen peroxide and lipid peroxides, yielding GSSG, while glutathione reductase regenerates GSH using NADPH. Glutathione S-transferases conjugate electrophiles to GSH, supporting detoxification and excretion.
Cells synthesize glutathione through two ATP-dependent enzymatic steps. The first step combines glutamate and cysteine to form gamma-glutamylcysteine, catalyzed by glutamate-cysteine ligase. The second step adds glycine, producing the complete tripeptide, catalyzed by glutathione synthetase. Glutathione itself can inhibit the first enzyme, providing negative feedback when levels are high. Because cysteine is often limiting, its availability influences how quickly the pathway proceeds. These reactions occur in the cytosol, and the resulting glutathione can be distributed to other compartments.
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its cysteine residue carries a thiol group, which allows the molecule to participate in reduction and oxidation reactions. The compound exists in most living cells, where the reduced form, often abbreviated GSH, is usually more abundant than the oxidized disulfide form, GSSG. Intracellular concentrations are commonly in the millimolar range, while extracellular concentrations are much lower. This uneven distribution supports its role as a major cellular redox buffer.
The alkali metals are among the most electropositive elements on the periodic table and thus tend to bond ionically to the most electronegative elements on the periodic table, the halogens (fluorine, chlorine, bromine, iodine, and astatine), forming salts known as the alkali metal halides. The reaction is very vigorous and can sometimes result in explosions. All twenty stable alkali metal halides are known; the unstable ones are not known, with the exception of sodium astatide, because of the great instability and rarity of astatine and francium. The most well-known of the twenty is certainly sodium chloride, otherwise known as common salt. All of the stable alkali metal halides have the formula MX where M is an alkali metal and X is a halogen. They are all white ionic crystalline solids that have high melting points. All the alkali metal halides are soluble in water except for lithium fluoride (LiF), which is insoluble in water due to its very high lattice enthalpy. The high lattice enthalpy of lithium fluoride is due to the small sizes of the Li+ and F− ions, causing the electrostatic interactions between them to be strong: a similar effect occurs for magnesium fluoride, consistent with the diagonal relationship between lithium and magnesium. The alkali metals also react similarly with hydrogen to form ionic alkali metal hydrides, where the hydride anion acts as a pseudohalide: these are often used as reducing agents, producing hydrides, complex metal hydrides, or hydrogen gas. Other pseudohalides are also known, notably the cyanides.
=== Cold mixed absinthe === Many modern absinthes are produced using a cold-mix process. This inexpensive method of production does not involve distillation, and is regarded as inferior for the same reasons that give cause for cheaply compounded gin to be legally differentiated from distilled gin. The cold mixing process involves the simple blending of flavouring essences and artificial colouring in commercial alcohol, in similar fashion to most flavoured vodkas and inexpensive liqueurs and cordials. Some modern cold-mixed absinthes have been bottled at strengths approaching 90% ABV. Others are presented simply as a bottle of plain alcohol with a small amount of powdered herbs suspended within it. The lack of a formal legal definition in most countries to regulate the production and quality of absinthe has enabled cheaply made products to be falsely presented as traditional in production and composition. In Switzerland, the only country with a formal legal definition of absinthe, any absinthe product not obtained by maceration and distillation or coloured artificially cannot be sold as absinthe.
Neurotoxins, which primarily affect the nervous systems of animals, such as ion channel toxins. These are found in many venomous taxa, including mambas, black widow spiders, scorpions, box jellyfish, cone snails, centipedes and blue-ringed octopuses. Myotoxins, which damage muscles by binding to a receptor. These small, basic peptides are found in snake (such as rattlesnake) and lizard venoms. Cytotoxins, which kill individual cells and are found in the apitoxin of honey bees and the venom of black widow spiders. A subclass of cytotoxins is the necrotoxins, which cause necrosis (i.e., death) in the cells and tissues they encounter. The complex venoms of vipers and bees contain phospholipases; viper venoms often also contain trypsin-like serine proteases.
, where distance is the direct (not logarithmic) distance in number of decades or "octaves" to the right the mass concentration is found. To translate from mass to molar concentration, the dividend (molar mass and the divisor (1000) in the division change places, or, alternatively, distance to right is changed to distance to left. Substances with a molar mass around 1000g/mol (e.g. thyroxine) are almost vertically aligned in the mass and molar images. Adrenocorticotropic hormone, on the other hand, with a molar mass of 4540, is 0.7 decades to the right in the mass image. Substances with molar mass below 1000g/mol (e.g. electrolytes and metabolites) would have "negative" distance, that is, masses deviating to the left. Many substances given in mass concentration are not given in molar amount because they haven't been added to the article. The diagram above can also be used as an alternative way to convert any substance concentration (not only the normal or optimal ones) from molar to mass units and vice versa for those substances appearing in both scales, by measuring how much they are horizontally displaced from one another (representing the molar mass for that substance), and using the same distance from the concentration to be converted to determine the equivalent concentration in terms of the other unit. For example, on a certain monitor, the horizontal distance between the upper limits for parathyroid hormone in pmol/L and pg/mL may be 7 cm, with the mass concentration to the right.
In 1548, the house steward of Cosimo de' Medici, the grand duke of Tuscany, wrote to the Medici private secretary informing him that the basket of tomatoes sent from the grand duke's Florentine estate at Torre del Gallo "had arrived safely". Tomatoes were grown mainly as ornamentals early on after they arrived in Italy. For example, the Florentine aristocrat Giovanvettorio Soderini wrote how they "were to be sought only for their beauty", and were grown only in gardens or flower beds. The tomato's ability to mutate and create new and different varieties helped contribute to its success and spread throughout Italy. However, in areas where the climate supported growing tomatoes, their habit of growing close to the ground suggested low status. They were not adopted as a staple of the peasant population because they were not as filling as other crops. Additionally, both toxic and inedible varieties discouraged many people from attempting to consume or prepare any other varieties. In certain areas of Italy, such as Florence, the fruit was used solely as a tabletop decoration until it was incorporated into the local cuisine in the late 17th or early 18th century. The earliest discovered cookbook with tomato recipes was published in Naples in 1692, though the author had apparently obtained these recipes from Spanish sources. Varieties were developed over the following centuries for drying, for sauce, for pizzas, and for long-term storage. These varieties are usually known for their place of origin as much as by a variety name.
Sources: en.wikipedia.org
As for the two cold wars thesis, the chief problem is that the two periods are incommensurable. To be sure, they were joined together by enduring ideological hostility, but in the post-World War I years Bolshevism was not a geopolitical menace. After World War II, in contrast, the Soviet Union was a superpower that combined ideological antagonism with the kind of geopolitical threat posed by Germany and Japan in the Second World War. Even with more amicable relations in the 1920s, it is conceivable that post-1945 relations would have turned out much the same. The usage of the term "Cold War" to describe the postwar tensions between the US- and Soviet-led blocs was popularized by Bernard Baruch, a US financier and an adviser to Harry Truman, who used the term during a speech before the South Carolina state legislature on April 16, 1947. Since the term "Cold War" was popularized in 1947, there has been extensive disagreement in many political and scholarly discourses on what exactly were the sources of postwar tensions. In the American historiography, there has been disagreement as to who was responsible for the quick unraveling of the wartime alliance between 1945 and 1947, and on whether the conflict between the two superpowers was inevitable or could have been avoided. Discussion of these questions has centered in large part on the works of William Appleman Williams, Walter LaFeber, Gabriel Kolko and John Lewis Gaddis.
Saffron likely originated in Iran, Greece, Mesopotamia, or Kashmir. Harold McGee states that it was domesticated in or near Greece during the Bronze Age. C. sativus is probably a triploid form of Crocus cartwrightianus, which is also known as "wild saffron". Saffron crocus was slowly propagated by humans throughout much of Eurasia and was later brought to parts of North Africa, North America, and Oceania. Several wild species of Crocus similar to the commercial plant are known to have been harvested in recent times for use as saffron. Crocus ancyrensis was used to make saffron in Sivas in Central Turkey, the corms were also eaten. Crocus cartwrightianus was harvested on Andros in the islands of the Cyclades, for medicinal purposes and the stigmas for making a pigment called Zafran. Crocus longiflorus stigmas were used for saffron in Sicily. Crocus thomasii stigmas were used to flavour dishes around Taranto, South Italy. In Syria the stigmas of an unknown wild species were collected by women and children, sun-dried and pressed into small tablets which were sold in the Bazaars. Not all ancient depictions or descriptions of saffron spice or flowers are certain to be the same species as the modern commercial species used for spice.
== Future == Two prequels, Cold War 1994 and Cold War 1995, were announced at the Hong Kong Cinema panel for 2025 Cannes Film Festival from Edko. Both films were shot simultaneously back to back in 2024 with Longman Leung returning as director and writer, in addition to new cast members including Daniel Wu, Terrance Lau and Wu Kang-ren. The story follows a younger MB Lee during the years leading up to the Handover of Hong Kong as he navigates the world between the triads, police force, and the colonial and elite circle. A first poster and teaser trailer for Cold War 1994 was released on June 17th, 2025, and officially released on May 1st, 2026, while Cold War 1995 is slated to release either in late 2026 or 2027.
The tomato (US: , UK: ; Solanum lycopersicum) is a plant whose fruit is an edible berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originated from western South America, and may have been domesticated there, in Mexico, or in Central America. The Spanish introduced tomatoes to Eurasia in the Columbian exchange in the 16th century. Tomato plants are vines, largely annual, and vulnerable to frost, though sometimes living longer in greenhouses. The flowers can self-fertilize. Modern varieties have been bred to ripen uniformly red, in a process that has impaired the fruit's sweetness and flavor. There are thousands of cultivars, varying in size, color, shape, and flavor. Tomatoes are attacked by many insect pests and nematodes and are subject to diseases caused by viruses, mildew, and blight fungi. The tomato has a strong savory umami flavor and is an important ingredient in cuisines around the world. Tomatoes are widely used in sauces for pasta and pizza, in soups such as gazpacho and tomato soup, in salads and condiments like salsa and ketchup, and in various curries. Tomatoes are also consumed as juice and in beverages such as the Bloody Mary cocktail.
Sources: en.wikipedia.org
GSH is the reduced form of glutathione, with a free thiol group on cysteine. GSSG is the oxidized disulfide form, created when two GSH molecules become linked. The two forms exist together, and their balance is often reported as the GSH/GSSG ratio in laboratory studies.
Glutathione is synthesized inside cells from amino acids rather than being classified as an essential dietary nutrient. Dietary sources can provide glutathione or its precursors, but digestion and absorption alter what reaches tissues. Research continues on how dietary intake relates to cellular glutathione levels.
The liver has high glutathione concentrations and uses the compound in conjugation and antioxidant reactions. These reactions are relevant to the processing of drugs, pollutants, and normal metabolic byproducts. Studies often examine liver glutathione as a marker of oxidative stress or detoxification capacity.
GSH is the reduced form with a free thiol group, while GSSG is the oxidized disulfide-linked dimer. Most assays distinguish the two because their balance reflects redox conditions. The names are not interchangeable.